Vol. XLIV. June, IQ2J. No. 6. 



BIOLOGICAL BULLETIN 



CERTAIN EFFECTS OF THE SALTS OF THE HEAVY 

 METALS ON THE FERTILIZATION REAC- 

 TION IN ARBACIA PUNCTULATA. 



LEIGH HOADLEY, 

 The Hull Zoological Laboratory, University of Chicago. 



I. Introduction 255 



II. Normal fertilization reaction in Arbacia 258 



III. Methods 258 



IV. Experiments 260 



a. Data on various metals 260 



b. Comparative tests 271 



c. Summary 274 



V. Discussion 275 



VI. Conclusions 277 



I. Introduction. 



At the suggestion of Prof. F. R. Lillie in the spring of 1921, 

 I began, the following summer, a study of the effects of the 

 heavy metals on the fertilization reaction in Arbacia punctulata. 

 I desire here to express my appreciation for his many helpful 

 suggestions and his aid in the interpretation of the results. 



Lillie ('21) found that copper salts completely prevent the 

 elevation of fertilization membranes in Arbacia even at such a 

 great dilution as 1 : 500,000, though the concentration of copper 

 chloride required for the suppression of cleavage is 1 : 62,500. 

 It is the purpose of the present set of tests to establish the effects 

 of a series of metallic salt solutions on the fertilization reaction 

 and by this means to throw more light on the initial events of 

 this reaction. The work was done during the summers of 

 192 1 and 1922 at the Marine Biological Laboratory at Woods 

 Hole, Massachusetts. 



The experiments brought out very clearly that there is a 



sharp distinction between the initial and the subsequent events 



255 

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